Brian forgets to say that 3D Coat is one of the first to propose in new Alpha version the technic of "Voxels" (Volumetric pixel, "grain of clay" ;)
http://en.wikipedia.org/wiki/Voxel
ps You must have new strong graphic Video card !

This remarkable little offering from Argile is certainly worth checking out for value should you need to sculpture, paint or add photographic texture your exported mesh: http://www.n-sided.com/3D/argile.php?rub=1

The three short videos on the home page demonstrate the modest aspirations of this neat package.

Ray